Causes of Transformer Oil Leakage

1. Analysis of the causes of oil leakage from transformers

1. Rubber seal failure and weld cracking

The transformer has many welding points and long welding seams, and the oil-immersed transformer is a collection of various welding and connections based on a steel plate welded shell. A 31500kVA transformer has more than 70 welding points in total, and the total length of the welding seam is nearly 20m, so there may be many leakage paths. The causes of direct leakage are rubber seal failure and weld cracking, pores, slag inclusions, etc.

2. Aging, cracking and deformation of sealant parts

Transformer leakage mostly occurs at connections, and more than 95% are mainly caused by sealants. The quality of sealant parts mainly depends on its oil resistance. Those with poor oil resistance will age faster, especially at high temperatures, which can easily cause aging and cracking of seals. Deterioration, deformation, and even failure may cause oil leakage from the transformer.

3. Manufacturing quality of transformer

During the manufacturing process of the transformer, the oil tank has many welding points, long welds, difficult welding, welding materials, welding specifications, processes, and technologies, etc., which will affect the welding quality, causing pores, blisters, false welding, and desoldering, resulting in oil leakage from the transformer. .

4. The plate butterfly valve is of poor quality

Another part of the transformer that often leaks is the plate butterfly valve. The common plate butterfly valve used in transformers produced earlier has a rough, thin connection surface and a single-layer seal. It is an obsolete product and can easily cause oil leakage in the transformer.

5. Improper installation method

The flange connection is uneven, and the force around the sealing gasket cannot be uniformly applied during installation, artificially causing non-uniform stress on the bolts around the sealing gasket; the flange joint is deformed and misaligned, causing the force on one side of the gasket to be larger and the force on one side to be smaller. The gasket on the side with less force will easily cause leakage due to insufficient compression. This phenomenon mostly occurs at the connection of the gas relay and the connection between the radiator and the body; another point is that when the sealing gasket is installed, the compression amount is insufficient or excessive. When the compression amount is insufficient, the operating temperature of the transformer increases and the oil becomes thinner, causing the transformer to become thinner. Oil leakage, excessive compression, serious gasket deformation, accelerated aging and shortened service life.

6. Improper consignment

During consignment and construction transportation, collisions of parts and improper lifting and transportation can cause damage and deformation of parts, open welding joints, cracks, etc., resulting in leakage.

HZKM-3 Lubricating Abrasion Tester